Syrian rebels made a new push into Damascus Wednesday, clashing heavily with troops in the rebellious suburbs of the capital and firing mortars at a presidential palace and a Palestinian refugee camp.

As violence flared in other parts of the country, Turkey said it was about to ask NATO to station "Patriot" air-defense missiles along its border with Syria to guard against violence spilling onto its territory.

Meanwhile, British Prime Minister David Cameron's office said his government has authorized direct contact with Syrian opposition military representatives in an effort to find a political solution to Syria's crisis. Britain, however, will not provide military aid.

Cameron toured a Syrian refugee camp in Jordan and said he wants to work with U.S. President Barack Obama on ending Syria's bloodshed.

"Right here in Jordan I'm hearing appalling stories of what has happened inside Syria, and one of the first things I want to talk to Barack about is how we must do more to try and solve this crisis," he said.

The government stronghold of Damascus has seen a surge in violence this week with some of the fiercest clashes in months. In recent days, opposition fighters also stepped up assaults on high-ranking supporters of President Bashar al-Assad in the capital.

Activists say fighting Tuesday killed 150 people across Syria, including casualties from air strikes, bombings and ground battles in Damascus and in Aleppo.

In Qatar, members of the Syrian opposition are meeting under pressure to form a truly representative government-in-exile. The main Syrian exiled opposition grouping, the Syrian National Council, is due to elect a new leader and executive committee Wednesday.

The SNC and other groups will then meet Thursday to form a new 50-member civilian group that will later choose a temporary government for Syria and coordinate with the revolt's military wing.

The Syrian conflict, which began as a protest movement against the rule of President Assad, is entering its 20th month. An estimated 36,000 people have died as the government crackdown against protesters developed into full-blown civil war.